Many devices, such as wind turbines or other turbine generators, may include power converter systems, such as to drive switching devices. Switching devices may be utilized to deliver power at a fixed frequency, for instance, such as to a power grid, or when driving high speed electric machines or high speed, high power electric motors. In some instances, high speed, high power electric motors may be utilized in industrial applications to power pumps, fans, blowers, or compressors. In addition, high speed, high power electric motors that operate at variable speed are increasingly required in a range of industrial, mining, and drilling activities. Further, the activities often require a relatively high degree of reliability. In operations such as crude oil pumping from remote global locations where access to pumping stations is difficult and time consuming, reliability of motor operation is necessary to prevent dangerous, costly, and extended outages.
A relatively high speed, high power electric motor may receive power from a source power supply. In many applications, the power signal that is output from the source power supply may be passed through a power converter prior to being input into the high speed, high power electric motor. A power converter system may be used to convert an input current or voltage, which may be a fixed frequency alternating current, a variable frequency alternating current, or a direct current, to an output current at adesired output frequency and voltage level. A converter system can include several power semiconductor switches such, as insulated gate bipolar transistors (“IGBT”), integrated gate commutated thyristors (“IGCT” or “GCT”), metal oxide semiconductor controlled thyristors (“MCT”), triacs, power transistors, field effect transistors (“FET”), or metal oxide semiconductor field effect transistors (“MOSFET”) that are switched at certain frequencies to generate the desired converter output voltage and frequency. Example semiconductor switches as described can be utilized to provide switched current paths to deliver power from the input, or power source, which may be at one frequency and voltage, to the output or load, which may require a different frequency and/or voltage. The input power may be converted to a high frequency alternating current prior to delivery to the semiconductor switches.
Relatively simple, sturdy, and reliable power converters are requisites for such high speed, high power motor operations. Converters, including multiple, individual components, may have an increased likelihood that any one individual component switch may randomly fail, driving down system reliability. Adding elements to the converters, such as snubber circuits for semiconductor switches, further increases the number of components that may fail. Moreover, in many existing solutions, multiple power converters are combined in parallel to drive the load or loads. Each power converter may drive one or multiple semiconductor switches and other peripheral components. When multiple power converters are combined as a single system, current solutions have a large number of individual components, driving down the reliability and increasing system costs.
Accordingly, there exists a need for improved power supply systems. There exists a further need for power supply systems that reduce the number of components, increasing reliability and reducing costs thereof.